I literally have 500GB external USB drives strewn all over the place with multiple copies of multiple things and I have NO clues what is where. So when I sat down to list the things I wanted, I came up with the following:

1. A central place in my Home Office to store all my backup, training videos, music, documents and pictures.
2. Accessible by Macs, Windows 7, Windows 8, Windows 8 RT and if possible on iOS.
3. Low powered, always on, Uninterrupted Power Supply backed.
4. Accessible over WiFi. All my machines are connected via WiFi and that includes my desktop. The only thing connected to the Router ‘was’ the printer. So my ‘Network Storage’ had to be available over wifi.

Full articles here (from The Lazy Blogger):
My Raspberry Pi Powered ‘Personal Cloud’
Completing my Pi powered personal (Media) cloud